Sometimes you see Ezreal casting it, sometimes a ward give you a heads up. Sometimes an ally pings it, sometimes your mobility spell is available and you're able to dodge.
But sometimes, despite all the methods I've listed, you just get by it. From the lowest rank to the highest people get hit by his ult even if they're aware it's coming and attempt to dodge it.
The conversation isn't about someone's ability to dodge it. I actually agree that it does more damage than necessary for how strong his new kit is, especially considering it's aoe and has no penalties any more. Add back the % damage reduction per unit hit and it would make him feel a lot better to fight against.